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给XML文档添加新 ”records”

黄舟
黄舟asal
2017-02-11 15:54:381472semak imbas

本文所举的例子与保存HTML格式数据至XML类似。在以往当表格被提交后,我们通常会创建一个新的文档,现在只要文档已经存在,那么直接添加就可以了。此种技术的使用与创建基本数据类似。

  在前面的文章里,我已经演示了如何使用XMLDOM。因此,我们可以直接进入本文的示例。

  我们需要考虑的第一件事是我们将用于添加新"记录"的HTML 表单。在"将HTML表单数据保存至XML"例子中我们已使用过此表单,只是更改了文件名,但代码是相同的。

  AddContact.html: 

<html> 
  <head> 
   <title> Contact Information </title> 
  </head> 
  <body> 
   <form action="processAdd.asp" method="post">  
   <h3>Enter your contact information</h3>  
   First Name:  
   <input type="text" id="firstName" name="firstName"><br> Last Name:  
   <input type="text" id="lastName" name="lastName"><br> Address #1:  
   <input type="text" id="address1" name="address1"><br> Address #2:  
   <input type="text" id="address2" name="address2"><br> Phone Number:  
   <input type="text" id="phone" name="phone"><br> E-Mail:  
   <input type="text" id="email" name="email"><br>  
   <input type="submit" id="btnSub" name="btnSub" value="Submit"><br>  
   </form> 
  </body> 
  </html>


  我们设置此HTML表单是来处理ADD。ASP的。这里的ASP 页面具有检测XML.文件及ROLODEX.XML是否存在的功能。如果它们确实存在,ASP则会在文件上附加新的条目,如果文件不存在,则需要创建。 

  Process Add.asp:  

<% 
   &#39;-------------------------------------------------------------------- 
   &#39;The "addNewContacttoXML" Function accepts two parameters. 
   &#39;strXMLFilePath - The physical path where the XML file will be saved. 
   &#39;strFileName - The name of the XML file that will be saved. 
   &#39;-------------------------------------------------------------------- 
   Function addNewContacttoXML(strXMLFilePath, strFileName)  
    &#39;Declare local variables.  
    Dim objDom  
    Dim objRoot  
    Dim objRecord  
    Dim objField 
    Dim objFieldValue  
    Dim objattID  
    Dim objattTabOrder  
    Dim objPI  
    Dim blnFileExists  
    Dim x  
    &#39;Instantiate the Microsoft XMLDOM.  
    Set objDom = server.CreateObject("Microsoft.XMLDOM")  
    objDom.preserveWhiteSpace = True 
    &#39;Call the Load Method of the XMLDOM Object. The Load ethod has a  
    &#39;boolean return value indicating whether or not the file could be  
    &#39;loaded. If the file exists and loads it will return true, otherwise, 
    &#39;it will return false. 
    blnFileExists = objDom.Load(strXMLFilePath & "\" & strFileName)  
    &#39;Test to see if the file loaded successfully.  
    If blnFileExists = True Then  
     &#39;If the file loaded set the objRoot Object equal to the root element  
     &#39;of the XML document.  
     Set objRoot = objDom.documentElement Else  
     &#39;Create your root element and append it to the XML document.  
     Set objRoot = objDom.createElement("rolodex")  
     objDom.appendChild objRoot 
    End If  
     &#39;Create the new container element for the new record.  
     Set objRecord = objDom.createElement("contact")  
     objRoot.appendChild objRecord  
     &#39;Iterate through the Form Collection of the Request Object. 
     For x = 1 To Request.Form.Count  
      &#39;Check to see if "btn" is in the name of the form element. If it is,  
      &#39;then it is a button and we do not want to add it to the XML  
      &#39;document".  
      If instr(1,Request.Form.Key(x),"btn") = 0 Then  
       &#39;Create an element, "field".  
       Set objField = objDom.createElement("field")  
       &#39;Create an attribute, "id".  
       Set objattID = objDom.createAttribute("id")  
       &#39;Set the value of the id attribute equal the the name of the current  
       &#39;form field.  
       objattID.Text = Request.Form.Key(x)  
       &#39;The setAttributeNode method will append the id attribute to the  
       &#39;field element. objField.setAttributeNode objattID  
       &#39;Create another attribute, "taborder". This just orders the  
       &#39;elements.  
       Set objattTabOrder = objDom.createAttribute("taborder")  
        
       &#39;Set the value of the taborder attribute.  
       objattTabOrder.Text = x  
       &#39;Append the taborder attribute to the field element.  
       &#39;objField.setAttributeNode objattTabOrder  
       &#39;Create a new element, "field_value". 
       Set objFieldValue = objDom.createElement("field_value")  
       &#39;Set the value of the field_value element equal to the value of the  
       &#39;current field in the Form Collection.  
       objFieldValue.Text = Request.Form(x)  
       &#39;Append the field element as a child of the new record container  
       &#39;element, contact. objRecord.appendChild objField  
       &#39;Append the field_value element as a child of the field element. 
       objField.appendChild objFieldValue  
      End If  
     Next  
     &#39;Check once again to see if the file loaded successfully. If it did  
     &#39;not, that means we are creating a new document and need to be sure to  
     &#39;insert the XML processing instruction.  
     If blnFileExists = False then  
      &#39;Create the xml processing instruction.  
      Set objPI = objDom.createProcessingInstruction("xml", "version=&#39;1.0&#39;")  
      &#39;Append the processing instruction to the XML document.  
      objDom.insertBefore objPI, objDom.childNodes(0)  
     End If  
     &#39;Save the XML document. 
     objDom.save strXMLFilePath & "\" & strFileName  
     &#39;Release all of your object references.  
     Set objDom = Nothing  
     Set objRoot = Nothing  
     Set objRecord = Nothing  
     Set objField = Nothing  
     Set objFieldValue = Nothing  
     Set objattID = Nothing  
     Set objattTabOrder = Nothing  
     Set objPI = NothingEnd  
    Function 
    &#39;Do not break on an error. 
    On Error Resume Next 
    &#39;Call the addNewContacttoXML function, passing in the physical path to 
    &#39;save the file to and the name that you wish to use for the file. 
    addNewContacttoXML "c:","rolodex.xml" 
    &#39;Test to see if an error occurred, if so, let the user know. 
    &#39;Otherwise, tell the user that the operation was successful. 
    If err.number <> 0 then  
     Response.write("Errors occurred while saving your form submission.") 
    Else  
     Response.write("Your form submission has been saved.") 
    End If 
   %>


如果你已经读过关于"将HTML 表单数据保存至XML格式"的文章,你会注意到附加到将HTML数据扩展到XML文件的代码与HTML数据扩展到新文档的代码基本上是一致的。但是这里还是有两个主要的不同点:

 &#39;Call the Load Method of the XMLDOM Object. The Load Method has a  
   &#39;boolean return value indicating whether or not the file could be  
   &#39;loaded. If the file exists and loads it will return true, otherwise,  
   &#39;it will return false.  
   blnFileExists = objDom.Load(strXMLFilePath & "\" & strFileName)  
    
   &#39;Test to see if the file loaded successfully.  
   If blnFileExists = True Then  
    &#39;If the file loaded set the objRoot Object equal to the root element  
    &#39;of the XML document.  
    Set objRoot = objDom.documentElement 
   Else  
    &#39;Create your root element and append it to the XML document.  
    Set objRoot = objDom.createElement("contact")  
    objDom.appendChild objRoot  
   End If

  本节的代码来自addNewContacttoXML 功能。因为我们不可能每次都新建一个文件,所以我们改为保存CONTACT。如果能够LOAD此文件呢,我们则获得了这个XML文档的根元素;如果不能够呢,那么我们就假设它不存在并创建一个新的要元素并将它附加到XML文档上。

  另外一个主要区别在于:当我们对文件进行二次检测,是否成功的LOAD,这样我们可以决定是否需要加上 一条处理指令。如果文件存在,我们就不需要加上这条指令。但是,如果创建了一个新的文件,那么则一定得加上这条处理指令。


&#39;Check once again to see if the file loaded successfully. If it did  
  &#39;not, that means we are creating a new document and need to be sure to  
  &#39;insert the XML processing instruction.  
  If blnFileExists = False then  
   &#39;Create the xml processing instruction.  
   Set objPI = objDom.createProcessingInstruction("xml", "version=&#39;1.0&#39;")  
   &#39;Append the processing instruction to the XML document.  
   objDom.insertBefore objPI, objDom.childNodes(0)  
  End If

  除开以上两点不同之处外,你可以发现 保存数据至新文件的代码实际上是与 附加新record至存在文件的代码是一样的。我们创建一个新的element, contact CONTAINER,以便能容下每个新添的RECORD。代码将会在Form Collection of the Request Objec中不断重复以创建适合的XML节点并将这些节点值设置得与当前Form Field.一样。

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